A 71-year-old female was hospitalized for uncontrolled hypertension and acute kidney injury. Her past medical history was significant for coronary artery disease with prior bypass grafting, heart failure with preserved ejection fraction, hypertension, and Type 2 diabetes mellitus. The patient was a former cigarette smoker and had been under considerable emotional stress following the death of her husband. During her initial hospitalization, the patient received temporary hemodialysis, her antihypertensive regimen was adjusted, and she showed clinical improvement. At the time of discharge, the patient was prescribed amlodipine 10 mg twice daily (with two refills), metoprolol 50 mg twice daily, doxazosin 2 mg daily, and torsemide 30 mg daily. 
Over the following 3 months, the patient developed worsening fatigue, lethargy, slow movements, a shuffling gait, personality changes, and a ‘stoic’ facial expression, while her blood pressure remained sub-optimally controlled. The patient was re-hospitalized for chest pain and underwent angioplasty. The patient was evaluated by multiple specialists and seen twice by her family physician. The patient was eventually diagnosed with anxiety and depression and started on citalopram and alprazolam.
The patient presented a third time to the emergency department after a fall, complaining of light-headedness and poor ambulation. On examination, the patient had a shuffling gait, bradykinesia, and a blank facial expression. Laboratory evaluation showed elevated creatinine, and a non-contrast CT of the head revealed no acute abnormalities. On admission, the patient’s medication reconciliation revealed she was taking metoprolol, doxazosin, alprazolam, citalopram, and thiothixene 10 mg twice daily. Review of her pill bottles revealed that her pharmacy had erroneously dispensed thiothixene (an antipsychotic) instead of amlodipine, which the patient had been taking dutifully for the past 3 months. The patient was diagnosed with drug-induced Parkinsonism secondary to thiothixene. The medication was discontinued, and the patient’s clinical status subsequently improved.